This application claims priority to an application entitled xe2x80x9cCircuit and Method for Preventing Erroneous Opening and Closing in Automatically/Manually Foldable Portable Radio Phonexe2x80x9d filed in the Korean Industrial Property Office on Sept. 26, 2000 and assigned Serial No. 2000-56435, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to an automatically/manually foldable portable radio phone, and in particular, to a circuit and method for preventing an erroneous opening and closing of a sub-body on a main body regardless of the phone being in an automatic mode or a manual mode.
2. Description of the Related Art
In general, portable radio phones are classified into a bar type and a folder type. A decreasing number of individuals use bar type terminals since a keypad portion is exposed from a main body. The foldable terminals have been developed in diverse forms so that a sub-body can be raised from or lowered to a main body to protect a keypad portion. The foldable terminals are also divided into a flip type characterized by use of a flip cover as a sub-body for protecting a keypad portion on a main body and collecting transmitted voice, and a flip-up type with a flip cover that is lifted upward from a main body. Such folder type terminals with LCD (Liquid Crystal Display) modules on their sub-bodies are popular in today""s mobile society.
To satisfy diverse demands of users, an automatically/manually foldable portable phone has recently been developed in which a sub-body can be placed automatically/manually in an open position and a closed position by simple switching on a main body, as disclosed in Korea Application No. 1999-49228. The main user requirement of the automatically/manually foldable portable phone is stable operation in the opening and closing of a folder in both an automatic mode and in a manual mode, and when powered-off. When a DC motor is used, the known automatically/manually foldable portable phone may experience erroneous opening/closing of a sub-body from/to a main body due to inverse electromotive force generated in the DC motor. In addition, asynchronous timing between power application to the motor and control of a motor rotating direction in an automatic mode causes erroneous opening/closing of the sub-body.
It is, therefore, an object of the present invention to provide a circuit for ensuring normal opening/closing of a sub-body regardless of an automatic mode or a manual mode in an automatically/manually foldable portable radio phone.
It is another object of the present invention to provide a circuit for ensuring normal opening/closing of a sub-body even when a battery is powered-off in an automatically/manually foldable portable radio phone.
It is a further object of the present invention to provide a circuit for ensuring normal opening/closing of a folder when switching between an automatic mode and a manual mode in an automatically/manually foldable portable radio phone.
It is still another object of the present invention to provide a circuit for preventing erroneous opening/closing of a folder caused by inverse electromotive force generated from a motor in an automatic/manual mode in an automatically/manually foldable portable radio phone.
It is yet another object of the present invention to provide a method of ensuring normal opening/closing of a sub-body in an automatic mode in an automatically/manually foldable portable radio phone.
The foregoing and other objects are achieved by a circuit for preventing erroneous opening and closing caused particularly by use of a DC motor in an automatically/manually foldable portable radio terminal having a main body and a sub-body rotatable with respect to the main body. In the circuit, a motor provides rotating force to automatically raise or lower the sub-body, a motor driver drives the motor according to a motor driving direction control signal, an inverse electromotive force eliminator eliminates inverse electromotive force by opening or shorting both terminals of the motor according to an automatic mode or a manual mode, and a motor power controller controls supplying a driving power voltage to the motor.